/TypeScriptRestAPIPubSubProfiling

This project explain the perfect example of Rest API , with dependency injection

Primary LanguageTypeScript

This project is the standard Rest API implementation of express js in Type script, Annotations ,logging,container, DI

  • This example give us litle demo of How Get,POST works using anotations

  • Focus on UserController, It demonstrate below points

    • How Class request mapping works(@JsonController)
      • You can see the get,post API.
      • You can see the path variable,(":id")
      • You can see the request param("email")
        • You can mark those as optional or mandatory
        • Only problem i can see is that, @QueryParam cant route the request
          • For example : Two mapping for "@Get("/users")", one with "email" and One with "limit"
        • While pathvariable , can route the request. like in case(:userID)
      • You can see the validation on User.ts 
            @IsPositive()
    public id: number;
        • This validation works while using in @Body,@QueryParam,@Param, basically the inputs from API.

  • Focus on MainServer.ts

    • You will find the default configurations.
      • you can provide more details , like cors,controllers,middlewares,defaults configs, contextPath

  • This project also explain about dependancy ingection.

    • you can see the UserDao is ingestion in UserController.
    • This happen because of typedi in mainServer.ts 
      useContainer(Container);

  • Read about the method overloading in type script, In UserDao, we have to create separate function, findById and findByEmail

    • TypeScript supports overloading based on number of parameters, but the steps to be followed are a bit different if we compare to OO languages. In answer to another SO question, someone explained it with a nice example: Method overloading?.

  • Create new project with nodeJs with express JS.

  • to add type script in project : yarn add typescript --dev

  • this project explain about the basics of project

  • nodemon is node application runtime. the difference between node and nodeman is

    • Nodeman takes the runtime changes and execute at the same time without re-starting the application

  • Execute below command in project directory where package.json file is present npm install npm start

  • This project also explain about below major points

    • Google pubsub
      • Check the PubSubService.ts -> It explain the message is consumed and handling error and max message at a time.
    • Profiling in typescript -> Check nodemon.json, we have provided env and used the same in config.ts.
      • Config.ts used the js-yaml to convert yml to json and json to object and did validation.
      • I had went through : https://github.com/motdotla/dotenv
        • I can see this is very easy for profiling , but problem is mandatory check and object mapping
        • hence handling the yaml file is easy and straight forward.

  • Things needs to explore more are

    • Open API spec
    • Hibernet validation like in Java -> This is done using the class-validation(check out config.ts)
    • Mysql connect to database
    • ORM like feature, Transaction handling
    • What is promise and related work
    • One more concept container in type script()

  • References :